Longitudinal Composite-Mode Linear Ultrasonic Motor for Motion Servo System of Probe Station

In order to build a motion system with high resolution, fast response, and long travel range in a probe station, a linear ultrasonic motor was investigated as an alternative to the electromagnetic counterpart in a servo system. This work focused on a longitudinal composite-mode linear ultrasonic motor for the motion servo system in a probe station. The motor was designed based on the required specifications. A finite element model was built to analyze the dynamic response of the stator. The influence of the structural parameters on the dynamic performances, i.e., sensitivity parameters, was calculated to analyze the stability of the structure. Based on these analytical works, a prototype of the stator was developed and mode testing was conducted. The experimental results showed that the proposed design was able to achieve respectable performance: Despite the dual-mode design, the frequency difference between the two working modes was minimized to 608 Hz; and the prototype could operate stably under 55.4 kHz, providing a 0.5 N load with 980 mm/s speed.

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Actuating Mechanism and Design of a Double Driving Feet Linear Ultrasonic Motor Using Longitudinal Vibration Transducer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.434-435.775 ◽

2010 ◽

Vol 434-435 ◽

pp. 775-778

Author(s):

Wei Shan Chen ◽

Ying Xiang Liu ◽

Jun Kao Liu ◽

Sheng Jun Shi

Keyword(s):

Transient Analysis ◽

Longitudinal Vibration ◽

Structural Parameters ◽

Ultrasonic Motor ◽

Longitudinal Vibrations ◽

Resonant Frequencies ◽

Vibration Transducer ◽

Linear Ultrasonic Motor ◽

Piezoelectric Coupling ◽

Vertical Vibrations

A double driving feet linear ultrasonic motor using longitudinal vibration transducer is proposed in this paper. The stator of proposed motor contains a horizontal transducer and two vertical transducers. The horizontal transducer includes two exponential shape horns located at the leading ends, and each vertical transducer contains one exponential shape horn. The horns intersected at the tip ends where located the driving feet. The horizontal and vertical vibrations of driving feet are generated by the longitudinal vibrations of horizontal and vertical transducers, respectively. Longitudinal vibrations are superimposed in the stator and generated elliptical motions at the driving feet. The two vibration modals of stator are gained with FEM, and the resonant frequencies of two vibration modals are degenerated by adjusting the structural parameters. Transient analysis of piezoelectric coupling states the good and strong elliptical motions of driving feet, and verifies the theoretical feasibility of proposed motor.

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A Compact Linear Ultrasonic Motor Composed by Double Flexural Vibrator

Micromachines ◽

10.3390/mi12080958 ◽

2021 ◽

Vol 12 (8) ◽

pp. 958

Author(s):

Jiayin Li ◽

Yin Wang ◽

Ziyan Chen ◽

Fang Cheng ◽

Qing Yu

Keyword(s):

Structural Parameters ◽

Ultrasonic Motor ◽

Local Deformation ◽

Frequency Difference ◽

Modal Testing ◽

Maximum Speed ◽

Element Analysis ◽

Linear Ultrasonic Motor ◽

Optimized Model ◽

Maximum Thrust

A minimized linear ultrasonic motor was proposed, and two flexural bimorph vibrators were utilized to form its stator. The construction of the linear ultrasonic motor and its operation principle was introduced. Two working modes with the same local deformation distribution were chosen on the basis of Finite Element Analysis (FEA). To obtain its optimized structural parameters, sensitivities on frequency difference were calculated, and a way of decreasing the frequency difference of two working modes was introduced. A prototype of the optimized model was made. The modal testing of the stator and its performance evaluation was conducted. The modal testing results were in good agreement with that of the simulation. The maximum speed of the prototype is 245 mm/s, and its maximum thrust is 1.6 N.

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Analysis of Speed Servo System of Pneumatic Manipulator Based RBF Neural Network PID Control

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.40-41.65 ◽

2010 ◽

Vol 40-41 ◽

pp. 65-70 ◽

Cited By ~ 1

Author(s):

Jing Luo ◽

Rui Bo Yuan ◽

Yu Bi Yuan ◽

Shao Nan Ba ◽

Zong Cheng Zhang

Keyword(s):

Neural Network ◽

Pid Control ◽

Hybrid Control ◽

Rbf Neural Network ◽

Servo System ◽

Fast Response ◽

Quick Response ◽

Pneumatic Servo System ◽

The Stability ◽

Neural Network Pid

Through analysis and comparison of simple PID control and RBF neural network-PID hybrid control of the pneumatic servo system, then compared the stability and quick response under the two control system. Concluded that RBF neural network-PID hybrid control has better stability and fast response than the simple PID control.

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Optimal Design for Stator of a New Linear Ultrasonic Motor

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.536-537.1047 ◽

2014 ◽

Vol 536-537 ◽

pp. 1047-1051

Author(s):

Shi Ping Sun ◽

Zheng Hu

Keyword(s):

Finite Element ◽

Optimal Design ◽

Theoretical Analysis ◽

Finite Element Model ◽

Element Model ◽

Ultrasonic Motor ◽

Wave Type ◽

Linear Ultrasonic Motor ◽

Working Frequency ◽

Bending Modes

In this paper, the working frequency band gap of ultrasonic motor (USM) was investigated under finite element model and experimental prototype. The findings indicate that the discrepancy between theoretical analysis and experimental test is mainly related to the fixation conditions of stator. This work proposes a new geometrical symmetrical stator for standing-wave-type linear USM to reduce the discrepancy. The first longitudinal and the second bending modes of stator are combined to drive the USM. Parameterized finite element model with actual boundary is developed to analyze and optimize the stator performance. The results show that the gap between working frequencies can be substantial reduced compared to the initial design.

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Design and Analysis of a Linear Ultrasonic Motor with Composite Bending and Torsional Vibration Modes

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.945-949.1327 ◽

2014 ◽

Vol 945-949 ◽

pp. 1327-1332 ◽

Cited By ~ 2

Author(s):

He Long Wang ◽

Wei Shan Chen ◽

Jun Kao Liu

Keyword(s):

Torsional Vibration ◽

Transient Analysis ◽

Structural Parameters ◽

Ultrasonic Motor ◽

Vibration Modes ◽

Bending Vibration ◽

First Order ◽

Linear Ultrasonic Motor ◽

New Type ◽

Working Principle

A new type linear ultrasonic motor using Second-order bending and First-order torsional modes (2B-1T) is proposed. The ultrasonic motor has two driving feet and the continuous linear motions of sliders are realized by the frictional force between stator and sliders. In this new design, bending vibration is excited by d33 mode, which controls the preload pressure, and torsional vibration is excited by d15 mode, which generates the driving force. The elliptical trajectories of both feet are achieved, when the phase difference of the two modes is 90° in time and space. The working principle of ultrasonic motor using 2B-1T is simulated. A parametric model of the stator is designed. The sensitive analyses of structural parameters are gained with modal analysis. The characteristics and trajectories of driver feet are studied by transient analysis. These results can provide theoretical basis for the development of this new type ultrasonic motor.

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Model Reference Adaptive Control on a Hydraulic Servo System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.268-270.505 ◽

2011 ◽

Vol 268-270 ◽

pp. 505-508

Author(s):

Zhi Yong Qu ◽

Zheng Mao Ye

Keyword(s):

Servo System ◽

Adaptive Controller ◽

Fast Response ◽

System Stability ◽

Servo Systems ◽

Hydraulic Servo ◽

Hydraulic Servo System ◽

Simulation Results ◽

The Stability ◽

Model Reference Adaptive

Hydraulic servo systems are usually used in industry. This kind of system is nonlinear in nature and generally difficult to control. The ordinary linear constant gain controller can cause overshoot or even loss of system stability. Application of adaptive controller to a nonlinear hydraulic servo system is investigated in this paper. The dynamic model of the system is given and the stability is also analyzed using Popov's criterion. The steady state error can be eliminated using adaptive controller combined with an integration term. Simulation results show the performance of adaptive controller with fast response and less overshoot

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Delay compensation based controller for rotary electrohydraulic servo system

International Journal of Dynamics and Control ◽

10.1007/s40435-020-00752-6 ◽

2021 ◽

Author(s):

Zakarya Omar ◽

Xingsong Wang ◽

Khalid Hussain ◽

Mingxing Yang

Keyword(s):

High Frequency ◽

Dead Time ◽

Sliding Mode ◽

Servo System ◽

Smith Predictor ◽

Delay Compensation ◽

Mechanical Parts ◽

System Output ◽

Electrohydraulic Servo System ◽

The Stability

AbstractThe typical power-assisted hip exoskeleton utilizes rotary electrohydraulic actuator to carry out strength augmentation required by many tasks such as running, lifting loads and climbing up. Nevertheless, it is difficult to precisely control it due to the inherent nonlinearity and the large dead time occurring in the output. The presence of large dead time fires undesired fluctuation in the system output. Furthermore, the risk of damaging the mechanical parts of the actuator increases as these high-frequency underdamped oscillations surpass the natural frequency of the system. In addition, system closed-loop performance is degraded and the stability of the system is unenviably affected. In this work, a Sliding Mode Controller enhanced by a Smith predictor (SMC-SP) scheme that counts for the output delay and the inherent parameter nonlinearities is presented. SMC is utilized for its robustness against the uncertainty and nonlinearity of the servo system parameters whereas the Smith predictor alleviates the dead time of the system’s states. Experimental results show smoother response of the proposed scheme regardless of the amount of the existing dead time. The response trajectories of the proposed SMC-SP versus other control methods were compared for a different predefined dead time.

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Stability Analysis of Different Regulation Modes of Hydropower Units

Energies ◽

10.3390/en14071933 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1933

Author(s):

Xinran Guo ◽

Yuanchu Cheng ◽

Jiada Wei ◽

Yitian Luo

Keyword(s):

Stable Operation ◽

Rotor Speed ◽

Frequency Range ◽

Power Regulation ◽

Normal Frequency ◽

Dynamic Performances ◽

Negative Damping ◽

The Stability ◽

Regulation Mode ◽

Water Inertia

The dynamic characteristics of hydropower unit governing systems considerably influence the stability of hydropower units and the connected power system. The dynamic performances of hydropower units with power regulation mode (PRM) and opening regulation mode (ORM) are different. This paper establishes a detailed linear model of a hydropower unit based on the Phillips–Heffron model. The damping characteristic and stability of two regulation modes with different water inertia time constants TW were analyzed. ORM tended to provide negative damping, while PRM often provided positive damping in the major parts of the frequency range within the normal frequency oscillations when TW was large. Eigenvalue analysis illustrated that PRM has better stability than ORM. To validate the analysis, a simulation under two typical faults WAS conducted based on a nonlinear model of a hydropower unit. The simulation results illustrated that the responses of units with PRM are more stable in terms of important operating parameters, such as output power, rotor speed, and power angles. For hydropower units facing challenges in stable operation, PRM is recommended to obtain good dynamic stability.

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